I've been using Soy Granuals for my source of PA (Phosphatidic acid) for its mTOR activating qualities, but soy-derived Lysophosphatidic acid and Phosphatidylserine have both been shown to induce an increase in mTOR signaling as well.
An interesting note is that PA from soy was found to be a more potent stimulator of mTOR signaling than that derived from egg sources.
Cited Study:
*Journal of the International Society of Sports Nutrition 2013, 10(Suppl 1)7
I would add that it has been shown that exercise induced stressors increase the effectiveness of these substances and thus enhance mTOR signalling to a greater extent. The study most cite had their subjects take PA both pre and post workout. One could draw the conclusion that Phosphatidylserine will also benefit from exercise stressors and thus the same dosing protocol.
Personally, I take about 3 tbsp of soy granuals pre, and 2 post.
Danes might have some more info on Phosphatidylserine and its ability to increase mTOR signalling.